To Tap or Not To Tap: When Ascites is Not Ascites
Ben Tomlinson MD (1), Heather Vierra MD (1), Rajendra Ramsamooj, MD ()
1. Department of Internal Medicine. 2. Department of Patholgy.
University of California, Davis Medical Center; Sacramento, CA
PATIENT’S COURSE
Z
INTRODUCTION
While ultrasound is the most sensitive and specific method of identifying ascities, most
texts and guidelines consider it optional prior to therapeutic paracentesis. We present
a case of desmoplastic small round blue cell tumor, a rare tumor most commonly seen
in young men and adolescents, feigning large volume ascites in a patient with shortness
of breath.
Patient’s CT scans with contrast from initial
presentation and after three cycles of
chemotherapy.
Bulky intrabdominal lymphadenopathy and liver
metastases are the primary findings. Arrows
highlight the displacement of the inferior vena
cava – highlighting the improvement with
therapy and the intrabdominal masses.
LEARNING OBJECTIVES
1. Discuss the use of ultrasound in therapeutic paracentesis with malignant ascites.
2. Review the presentation, epidemiology, and pathological characteristics of
desmoplastic small round blue cell tumor (DSCT).
THE CASE: A 21 year old man
Background: Patient was diagnosed with DSCT during a previous admission 5 months
prior to presentation. Chief complaint at the time was abdominal distension and weight loss
occurring over several weeks to months. Initial workup revealed diffuse large abdominal
lymphadenopathy, and a 10x15cm pelvic mass. Core needle biopsy of mass identified
DSCT. Patient was offered chemotherapy at time of diagnosis but chose to forgo therapy
against medical advice and was discharged home. There was no further interaction with the
health system until second presentation.
Chief Complaint: Shortness of breath, leg edema and abdominal distension
History of Present Illness: Patient reported that since his prior discharge, he returned to his
daily routine as best as possible. Prior to this presentation, patient reported that his
abdominal distension had become significantly worse over the few weeks preceding also
with progressive leg swelling. His feet became swollen to the point where ambulating
without assistance was very difficult. Moreover, over the final 2-3 days he reported
increasing dyspnea on exertion that had reached the point where he had the sensation at rest.
Additional review of systems was otherwise negative
Past Medical History: Only significant for his previous admission and cancer diagnosis.
There was no significant family or surgical history.
Physical Exam: Vitals Signs – P: 145 RR: 28 T: 38.5 BP: 132/92 SpO2: 95% on RA
General Appearance: thin, cachetic young man in moderate distress..
Mouth: moist mucous membranes, normal dentition, no throat erythema.
Neck: Thin
Lymphadenopathy: no cervical, supraclavicular, submandibular, submental, periauricular,
occipital lymphadenopathy, or axillary lymphadenopathy
Heart: tachycardic, but normal s1,s2 no murmurs, gallops, or rubs .
Lungs: Very short lung fields, but no obvious wheezes, crackles, or rhonchi
Abdomen: no audible bowel sounds, very distended, taught, dull to percussion diffusely.
No obvious fluid wave, and tests for shifting dullness were equivocal.
Genitourinary: scrotal edema
Extremities: +2 radial and dorsalis pedis pulses, +3 pitting lower extremity edema, equal
bilaterally.
Patient’s CT scan identified large pleural effusion that contributed to patient’s
compressive atelectasis. He received thoracentesis with immediate relief of his shortness of
breath. Patient remained an inpatient to start a modified course of chemotherapy generally
used for Ewing’s sarcoma. He received a pleural catheter to control his malignant pleural
effusion. Patient was ultimately discharged. Five months later, he has completed three cycles
of chemotherapy with significant improvement in his weight, abdominal distension, and
functional status, as well as control of his pleural catheter.
Initial Presentation
DISCUSSION
Ultrasound for paracentesis
After 3 cycles of chemotherapy
Second Presentation
Non-contrast CT scan from
second presentation.
Patient’s abdominal girth is
primarily from solid growth
of tumor (arrows) with only
very small areas of ascites.
Scout image from CT
scan – highlight’s the
patient’s profile at his
second presentation
Ultrasound of
Abdomen.
Demonstrates solid
appearance of
abdominal
metastases.
Desmosplastic Small Round Blue Cell Tumor
(DSCT)
DSCTs are a rare neuroendocrine tumor with sarcoma-like features. Initially described
in the 1980s as a distinct tumor, they are primarily a disease of young persons with male
predominance (5:1). The tumor’s course is aggressive and prognosis is typically poor.
Patients will typically respond to chemotherapy for several months before the disease relapses.
This patient’s presentation is classic for this tumor type. He initially presented with
abdominal distension and cachexia. Moreover, on his later presentations, despite the high
intraabdominal tumor burden, this patient displayed no symptoms of bowel or bladder
obstruction, which prior case series have also noted as a feature. Knowledge of this tumor
type can be important, even for the general internist, as cases can be confused with other
malignancies. Indeed, the initial working diagnosis for this patient was lymphoma prior to
biopsy. Confusion regarding the diagnosis can persist if an institution’s pathology department
is unfamiliar with this rare tumor . DSCT should be included in the differential diagnosis of
any young person, especially men, with new, large intrabdominal mass.
Histology of patient’s tumor demonstrates
the classic description of DSRBC tumor
cells. On the left, small round cells are
found along with desmoplastic stroma
(arrows).
Laboratory:
On the right, a high power view
demonstrates the high nucleus-tocytoplasmic ratio in a group of cells
surrounded by desmoplastic stroma.
Imaging:
REFERENCES
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Excluding the surrounding stroma, these
cells are morphologically similar to other
small round cell tumors, such as Ewing’s
sarcoma, or neuroectodermal tumors.
Chest X-Ray: Noted to be compatible with ascites with compressive atelectasis and marked
volume loss in the lungs
CT Scans and ultrasound are displayed in figures 1 and 2.
For many practicing physicians, the use of ultrasound to identify ascites prior to large
volume paracentesis has become almost routine. Yet clinical guidelines, including suggested
guidelines for cancer patients in palliative settings, generally advocate that ultrasound
continues to be optional. This patient’s personal history of two-to-three weeks of worsening
distension with history of malignancy, development of shortness of breath and the presence of
the most sensitive physical exam findings of distension and lower extremity edema were
highly suggestive of new onset large volume ascites. However, the use of ultrasound only
identified small pockets of ascites. An attempted paracentesis may have placed the patient at
risk of complication, and delayed the diagnosis of his pleural effusion as a significant
contributor to his shortness of breath.
Most guidelines cite a case series of ultrasound for paracentesis published in JAMA in
the 1980s by Bard et al. Yet, this article’s purpose was to advocate for more frequent use as
ultrasound was found to identity small bowel or other hazards near the site of paracentesis in
many patients. Admittedly, published case series of paracentesis generally find rates of
complications less than 1%, even without ultrasound, and no studies have directly compared
paracentesis with or without it. However, studies on numerous other procedures suggest
improved complication rates with ultrasound visualization. Given the already wide clinical
practice, it may be time for guidelines to be updated.
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Histology Figure 1 – Low Power
Histology Figure 2 – High Power
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